Manufacture of artificial threads or the like



J in this process.

Patented Dec. 15, 1931 UNITED sTA'rss PATENT OFFICE" WILHELM ELLER, O'FBERLINWILMERS.DORF,AND RICHARD HOFS'IADT, OF WOLFEN,

KREIS BITTERFELD, GERIMANY, ASSIGNORS TO I. G. FARBEN'INDUSTRIE AKTIEN-GESELLSCHAFT, OF FBANKFORT-ON-THE-MAIN, GERMANY, A CORPORATION OFGERMANY MANUFACTURE OF ARTIFICIAL THREADSOR THE LIKE m, Drawing.Application filed May 31, 1929, Serial No. 367,612, and in Germany June2, 1928.

The present invention relates to a new process of manufacturingartificial silk, threads, bands, 'horse hairs, films, etc. from viscoseand to the new precipitatingbath employed It is based on the observationthat halogenated fatty acids have a favorable influence on the operationof coagulating viscose. According to the invention halogenated fattyacids as for instance mono di-, trl-chloracetic acid are added to thecoagulating bath whereby products of good properties are pbtained. Forinstance in the'case of spinning artificial threads or hands fromViscose, the presence of such acids in the bath lends to the products atensile strength, extenslbihty, lustre and capacity for being dyed whichsuit all requirements.

The use of halogenated fatty acids is not associated with any particularbath. They may be used in any known bath provided, of course. that thebath does not react with halogenated fatty acids in an undesirablemanner. For example, the spinning baths consisting of sulfuric acid andsulfuric acid salts in which artificial silk is commonly made may bemixed with one or more halogenated fatty acids. When departing from theusual spinning baths containing sulfuric acid and sodium sulfate,halogenated fatty acids may also be added without change of the bath.but it may be advantageous to substitute the halogenated fatty acid fora more or less considerable portion of the mineral acid constituents ofthe spinning bath.

The nature of the halogenated fatty acid and the proportion which isadded to the bath depend merely on the question of solubility. Forexample. the easily soluble monochloracetic acid may be added in veryconsiderable proportions in a quantity of for instance per cent, whereastrichloracetic acid is only slightly soluble in many of the usual baths.We prefer to add about 100 grams per liter of monochloracetic acid tothe precipitating bath, the quantity, however, depending on the otheringredients of the bath and the best results may be ascertained by asimple test. Obviously, we may use a mixture of the'halogenated fattyacids with the same effect, c

The chief effect of the halogenated fatty acid in the'bath is that itmodifies the conditions of coagulation, for instance the speed of theaction of the mineral acid is varied and thereby a product of goodsoftnessobtained. Moreover, by the use of such a spinning bath one is inthe position to obtain under various conditions of maturity of viscose afiber of constant good physical properties, such as.

tensile strength, pliability and lustre.

The action of the halogenated fatty acid can be considerably increasedby using the acid in the form of an intermediate bath, through which thethreads pass after'they have left the spinning bath and before they arewound on the spools. The length of immersion in sucl an intermediatebath depends on the degree of concentration of the bath liuor.

ith the action of halogenated fatty acids on forms of viscose asdescribed above, there maybe associated with special advantage astretching of the form produced, for instance in spinning viscose toform artificial silk the addition of a halogenated fatty acid makes itpossible to apply a very considerable tension tothe thread, since thecoagulating effect is diminished by the halogenated fatty acid andcorrespondingly the thread remains longer in a plastic condition when ithas left the spinning nozzles than it does in baths which do not containhalogenated fatty acid.

The following examples illustrate the invention, which, however, is notlimited to the specific details'given therein Example 1.A viscosesolution containing 7 5 per cent of cellulose and having a ripeness of 4titrated with sodium chloride solution, is pressed through a nozzle with60 openings of about 0.09 mm. diameter in. a precipitating bathcontaining 13.5 per cent ofsulfuric acid, 31 per cent of sodium sulfateand 55.5 per cent of water. The drawing speed is held at about metersper minute, and the viscose pump deliverssuch a quantity of viscose thatthe bundle of threads obtained, has a titer of 120 deniers;

The threads are stretched by guiding them over glass roods. Thetemperature of this precipitating bath is kept at about 50 C. Afterhaving passed this precipitating bath, the threads are guided in asecond bath containing per cent of monochloracetic acid and 25 per centof water, this second bath being kept at a temperature of 22 C. Thethreads obtainable in this manner have a tensile strength of about 250grams per 100 deniers and an extensibility of about 8.5 per cent.

Example Q.A viscose solution containing 7.5 per cent of cellulose and7.5 per cent of alkali and having a normal ripeness, is spun into aprecipitating bath containing 13.5 per cent of sulfuric acid, 31 percentof sodium sulfate, 10 per cent of monochloracetic acid and 45.5 per centof water. The threads may be stretched by guiding them on their way fromthe nozzle to the collection device over glass roods or through asuitable thread guide known in the art. The precipitating bath is keptat a temperature of about 50 (1., the drawing speed may be maintained atabout 50-60 meters per minute. The threads obtainable have a tensilestrength of about 230 grams per 100 deniers and an extensibility ofabout 710 per cent.

Example 3.A viscose solution is spun under the same conditions asmentioned in Example 2, the precipitating bath, however, containsinstead of monochloracetic acid trichloracetic acid. ities are obtained.

What we claim is V 1. The process which comprises bringing viscose intothe form of threads, bands, horsehairs, films and treating it in 'abathbontaining a chlorinated fatty acid.

2. The process which comprises bringing viscose into the form ofthreads, bands, horsehairs, films and treating it in a bath containingmonochloracetic acid.

3. Process for manufacturing artificial threads, bands, films or thelike from a. viscose solution which comprises pressing a. viscosesolution in a precipitating bath containing a halogenated fatty acid.

4. Process for manufacturing artificial threads, bands, films or thelike from a viscose solution which comprises pressing a viscose solutionin a precipitating bath containing sulfuric acid and a halogenated fattyacid.

5. Process for manufacturing artificial threads, bands, films or thelike from .a viscose solution which comprises pressing a viscosesolution in a precipitating bath containing sulfuric acid, sodiumsulfate and a halogenated fatty acid.

6. Process for manufacturing artificial threads, bands, films or thelike from a viscose solution which comprises pressing a viscose solutionin a precipitating bathcon- Threads of similar qualtaining sulfuricacid, sodium sulfate and a chlorinated acetic acid.

7. Process for manufacturin artificial threads, bands, films or the li efrom a viscose solution which comprises pressin a viscose solution in aprecipitating bat containing sulfuric acid, sodium sulfate andmonochloracetic acid.

8. Aprecipitating bath containing a chlorinated fatty acid and suchproducts as are known in the art of spinningartificial fibers to besuitable to precipitate a viscose solution.

9. A precipitating bath containing sulfuric acid, sodium sulfate andmonochloracetic acid.

10. Process for manufacturin artificial threads, bands, films or thelike rom a viscose solution which comprises pressing a viscose solutionin a precipitating bath containing sulfuric acid, sodium sulfate andtrichloracetic acid.

11. A precipitating bath containing sulfurc acid, sodium sulfate andtrichloracetic acl In testimony whereof, we aflix our signatures.

WILHELM ELLER. RICHARD HOFSTADT.

